commit

Perform a batch update of the cache. Add all DataCachePCData
objects in additions and in
newUpdates, make the appropriate modifications to
all DataCachePCDatas in existingUpdates, and delete all
OIDs in deletes.
All changes made to cached data must be made via this
method. It is this method that is responsible for performing
any side-effects that should happen on meaningful cache changes.
Implementations should bear in mind that the
deletes collection may contain oids that are also
in the additions map. This is possible because it
is valid for a user to delete an object with a particular oid
and then add that object in the same batch.

additions - A collection of DataCachePCData objects.
These represent data that have been newly created,
and thus must be added to the cache.

newUpdates - A collection of DataCachePCData objects.
These represent data that have been modified but
were not originally in the cache, and thus must be added to the cache.

existingUpdates - A collection of DataCachePCData objects.
These represent data that have been modified and
were originally loaded from the cache. It is
up to the cache implementation to decide if
these values must be re-enlisted in the cache.
Some caches may return live data from DataCache.get(java.lang.Object)
invocations, in which case these values need not be re-enlisted.

deletes - A collection of object IDs that have been deleted
and must therefore be dropped from the cache.

pin

Pin the value stored under oid into the cache.
This method guarantees that oid's value will not
be dropped by the caching algorithm. This method does not
affect the behavior of DataCache.remove(java.lang.Object).

unpin

Unpin the value stored under oid from the cache.
This method reverses a previous invocation of DataCache.pin(java.lang.Object).
This method does not remove anything from the cache; it merely
makes oid's value a candidate for flushing from the cache.